ZSPM1025A
True Digital PWM Controller (Single-Phase, Single-Rail)
Additionally, in order to improve the accuracy of the current measurement, which can be adversely affected by the
temperature coefficient of the inductor’s DCR, the ZSPM1025A features temperature compensation via external
temperature sensing. Therefore, the temperature of the inductors is measured with an external temperature-
sensing element placed close to the inductor. This information is used to adapt the gain of the current sense path
to compensate for the increase in actual DCR.
3.3.7.
Temperature Measurement
The ZSPM1025A features two independent temperature measurement units. The internal temperature sensing
measures the temperatures inside the ZSPM1025A. The external temperature sensor is placed on the Murata
Power Block. The ZSPM1025A drives 60µA into the external temperature-sensing element and measures the
voltage on the TEMP pin. The Pink Power Designer™ GUI must be used to select the offset for configuration of
the external temperature measurement. A temperature-offset calibration is highly recommended.
3.4. Fault Monitoring and Response Generation
The ZSPM1025A monitors various signals during operation. Depending on the selected configuration, it can
respond to events generated by these signals. A wide range of options is configurable via the Pink Power
Designer™. Typical monitoring within the ZSPM1025A is a three-step process. First, an event is detected via a
configurable set of thresholds. This event is then digitally filtered before the ZSPM1025A reacts with a defined
response depending on the fault condition. For most monitored signals, a warning and a fault threshold can be
configured. A warning typically sets a status flag (see section 4.7.6) but does not trigger a response; whereas a
fault also generates a response.
The warning and fault events can be enabled for each parameter that the ZSPM1025 monitors (see Table 3.1).
The SMBALERT signal is asserted by the ZSPM1025A for any warning or fault that has been enabled. An
overview of the faults that the ZSPM1025A can detect and the response to each fault is given in Table 3.1.
Table 3.1
Fault Configuration Overview
Fault Response Type
Output Over-Voltage
Output Under-Voltage
Input Over-Voltage
Low impedance
Low-impedance
Off
Input Under-Voltage
Over-Current
Off
Low-impedance
External Over-Temperature
Internal Over-Temperature
Off
Off
The ZSPM1025A supports different response types depending on the fault detected. An “Off” response ramps the
output voltage down using the falling-edge sequencer settings. The final state of the output signals depends on
the value selected for VOFF_nom. The “low-impedance” response clamps the PWM output to PGND.
The controller fault handling will infinitely try to restart the converter on a fault condition. In analog controllers, this
infinite re-try feature is also known as “hiccup mode.”
© 2013 Zentrum Mikroelektronik Dresden AG — Rev. 1.00
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the
prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
Data Sheet
October 24, 2013
20 of 46
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